The overall goal of this program is to develop an oxygen concentrator capable of concentrating ambient air to near 100% oxygen for use in home oxygen therapy. Three types of oxygen source are used at present for home oxygen therapy. They are compressed oxygen, liquid oxygen and oxygen concentrators. These systems suffer from the disadvantages of high cost, need for frequent maintenance and bulk volume and weight. We propose here a novel electrochemical method to concentrate oxygen at a very low power consumption. The overall objective in Phase I is to determine the feasibility of using novel thin monolithic solid polymer electrolyte (SPE) composites for electrochemical concentration/purification of O2. Composites will be prepared from various electronically conductive materials and several separators, such as microporous films and ion-exchange membranes. These will be tested with O2 and an alternative anode depolarizer to determine cell voltage, current efficiency and power requirements. Some of the advantages anticipated over conventional methods are expected to include: lower power consumption at higher rates of O2 production, more compact, lighter weight devices with longer useful life and little maintenance. In Phase II a prototype will be built and demonstrated.